Alternate name: Bank identification number (BIN)Acronym: IIN
For example, let’s say your credit card number is 5412 7512 3412 3456. If your issuer uses a six-digit IIN, then the digits 541 275 make up the IIN on your card. If your issuer uses an eight-digit IIN, then your IIN is 5412 7512.
How Issuer Identification Numbers Work
Every time a payment card is used, the merchant’s bank needs to know which bank issued the customer’s card in order to route, clear, and settle the transaction. It uses these identification numbers—the IIN—since it can’t physically see the issuer’s logo on the card. The first digit in an IIN signifies the major industry identifier (MII). In a credit card context, the MII typically signifies the credit card network. The digits in the IIN following the first digit signify the credit card issuer, such as a bank or other financial institution. These numbers are known as bank identification numbers (BINs). If your card number began with the IIN 370 277, it would indicate that it was an American Express card issued by Wells Fargo. IIN guidelines are set by the International Standards Organization (ISO) in its ISO/IEC DIS 7812 standard. These are standardized worldwide, so an IIN can reliably identify the issuer behind a particular card. For efficient distribution, the ISO first assigns blocks of IINs to an administrative blockholder or a card scheme blockholder. These institutions act as intermediaries between the ISO and card issuers, and will issue INNs to credit-card issuers While all IINs used to be made up of six digits, the ISO expanded them to eight digits in 2017. Existing issuers with a six-digit IIN were given access to 100 eight-digit IINs based on their original six-digit codes. Of course, just because the ISO made this change to the IIN standard doesn’t mean it had immediate effect. Mastercard and VISA will only begin assigning eight-digit IINs beginning in April 2022.
Issuer Identification Number vs. Primary Account Number
Payment card numbers are made of more than just the IIN. The last eight to 19 digits of a card are the primary account number (PAN). While the IIN is associated with the card issuer, the PAN is associated with the individual cardholder.
